A SIM card is an abbreviation for “Subscriber Identity Module card”, which can also be called smart card or ID card. The SIM card can store user's data, authentication algorithm and key for identifying the subscriber identity by a GSM system. A mobile phone cannot be used without the SIM card. The SIM card is usually positioned in a SIM card seat of the mobile phone.
With the progress of science and the development of mobile communication, the mobile phone is continuously updated in construction, design and performance. In the present market, there are lots of types of mobile phones, and also lots of types of SIM cards fit for the mobile phones. For example, most types of mobile phones use a normal SIM card, while IPHONE 4 and IPHONE 4s use a Micro SIM card, and IPHONE 5 uses a Nano SIM card. The conventional SIM card seat has a card case for receiving the SIM card, and a signal terminal for conducting with the SIM card.
Due to the structural limitation, the SIM card seat of a type of mobile phone can only match a corresponding type of SIM card. That is, one type of mobile phone can only be suitable to receive one type of SIM card. For example, for IPHONE 4, the Micro SIM card cannot be replaced with a Mini SIM card. Therefore, when a user changes his/her mobile phone, he or she has to choose a mobile phone having the same type of SIM card seat in the case that he or she does not want to change the SIM card. Or the user has to give up his/her original SIM card to choose a mobile phone having a different type of SIM card seat to fit for a different type of SIM card, which may be inconvenient for the user and result in waste of resources.